CRRT treatment
The indications for CRRT in our study were as follow: 1) hypercreatinemia or azotemia (creatinine levels of >2 mg/dL; 2) blood urea nitrogen levels of >40 mg/dL); 3) oliguria (urine output of <0.5 mL/kg/h); 4) fluid overload >10%; 5) acute liver failure complicated with hepatorenal syndrome or hyperammonaemia; 6) severe electrolyte imbalance which did not respond immediately to conventional therapy (hyperkalaemia >7 mmol/L; hypernatraemia>160 mmol/L or hyponatraemia<110 mmol/L).
Vascular access was obtained with 5F dual-lumen ( Arrow, Teleflex Inc, Limerick, PA, USA), 6.5F–12F central venous catheters (GamCath; Gambro, Colombes, France) in the right internal jugular or femoral vein, according to patient body weight.
Two CRRT devices were used, including the Plasauto iQ21 (Asahi KASE, Japan), and PRISMA flex (Gambro Renal Products, France). Polyacrylonitrile AN69 or polysulfone hollow-fibre haemofilters were used, depending on the body surface area of the patient and on the pump employed. M10 filters (Gambro Renal Products, France) or AEF-03(Asahi KASE, Japan) were used in children weighing less than 5 kg; M60 (Gambro Renal Products, France) or (Asahi KASE, Japan) was used in patients weighing between 5 and 35 kg, and M100 (Gambro Renal Products, France) or AEF-10 (Asahi KASE, Japan) in children weighing over 35 kg. Thirty-three patients (63.5%) received CVVH, and nineteen patients (36.5%) received continuous venovenous hemodiafiltration (CVVHDF) with an ultrafiltrate flow rate of 35–50 mL/kg/hr. Hemofilters changes were scheduled every 24h or when clotted.
The dosage of was 5-20U/kg.h to maintain activated partial thromboplastin time (APTT) with 1.5-2 folds of normality during CRRT. Anticoagulation was achieved with heparin adjusted to a target activated partial thromboplastin time (APTT) of 41.5- to 2-fold of normal value. The regional citrate anticoagulation (RCA) procedure was conducted according to the guidelines from the Prismaflex operator’s manual. When sodium citrate was used as anticoagulation, the target post-filter ionized calcium level of 0.25–0.35 mmol/L was maintained. The citrate effect was neutralized using a continuous calcium infusion of 10% calcium gluconate to maintain ionized calcium blood levels between 1.0 and 1.2 mmol/L.